The objective of this collaborative clinical research effort is to improve the care of patients with bladder carcinoma through studies of different aspects of clinical management. The studies are carried out in several institutions simultaneously according to well-designed protocols. A central laboratory is responsible for the uniform collection, classification and analysis of pathologic and cytologic material and all data are being collected, organized, and analyzed in a central statistical office. In each participating institution, follow up of patients entered into the following protocols in continuing: Surveillance of all patients admitted with bladder carcinoma; the study of multiple mucosal biopsies from patients with frank tumor and/or positive cytology; evaluation of different forms of intravesical therapy, invasive carcinoma, radiotheraphy alone and preoperative radiotherapy followed by cystectomy. The following protocols have been initiated: studies of systemic chemotherapy in patients with metastic bladder carcinoma (Protocol 5) studies of adjuvant systemic chemotherapy in association with definitive therapy of invasive bladder carcinoma (Protocol 7); and studies of intervention (secondary prevention) in patients with completely resected low-stage lesions (Protocol 6).